Thermoplastic polyolefin compositions

Abstract

This invention relates to a thermoplastic polyolefin composition with (a) a polypropylene having a melting point of greater than 130° C. and a melt flow rate from 10 to 80 g/10 min; (b) an ethylene-propylene copolymer with 40 wt % to 80 wt % ethylene derived units and a Mooney Viscosity (1+4, 125° C.) of greater than 20 Mooney units, a Mw/Mn of from 1.8 to 4.0, and a weight average molecular weight of 50,000 to 300,000 g/mole; and (c) a propylene-based elastomer having 5 wt % to 25 wt % ethylene derived units and having a melting point of less than 110° C. and a Mw/Mn from 2.0 to 4.0; wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least four times greater than the room temperature notch impact of a composition without the propylene-based elastomer.

The invention claimed is: 
     
       1. A thermoplastic polyolefin composition comprising:
 a polypropylene having a melting point temperature (T m ) of greater than 130° C. and a melt flow rate (230° C./2.16 kg) within the range from 10 g/10 min to 80 g/10 min; 
 an ethylene-propylene copolymer comprising within the range from 40 wt % to 80 wt % ethylene derived units and having a Mooney Viscosity (1+4, 125° C.) of greater than about 20 Mooney units, a Mw/Mn within the range from 1.8 to 4.0, and a weight average molecular weight (Mw) within a range of from 50,000 g/mole to 300,000 g/mole; and 
 a propylene-based elastomer having within the range from 5 to 25 wt % ethylene derived units and having a melting point temperature (T m ) of less than 110° C. and a Mw/Mn within the range from 2.0 to 4.0, 
 wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least twenty times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
 
     
     
       2. The thermoplastic polyolefin composition of  claim 1 , wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least thirty times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
     
     
       3. The thermoplastic polyolefin composition of  claim 1 , wherein the room temperature notch impact of the composition is greater than about 9 ft-lb/in. 
     
     
       4. The thermoplastic polyolefin composition of  claim 1 , wherein the polypropylene is present within a range of from 50 wt % to 90 wt %; and the ethylene-propylene copolymer is present within a range from 10 wt % to 40 wt %; and wherein the propylene-based elastomer is present to within a range from 1.0 wt % to 10 wt %, each based on the weight of all ingredients of the composition. 
     
     
       5. The thermoplastic polyolefin composition of  claim 1 , wherein the polypropylene has a melt flow rate (MFR) of greater than about 35 g/10 min. 
     
     
       6. The thermoplastic polyolefin composition of  claim 1 , wherein the weight average molecular weight (Mw) of the propylene-based elastomer is at least 150,000 g/mole. 
     
     
       7. The thermoplastic polyolefin composition of  claim 1 , wherein the composition has a total ethylene content within the range of 6 to 24 wt %. 
     
     
       8. An automotive component made from the thermoplastic polyolefin composition of  claim 1 . 
     
     
       9. A thermoplastic polyolefin composition comprising:
 from 55 wt % to 75 wt %, by weight of the composition, of a polypropylene having a melting point temperature (T m ) of greater than 130° C. and a melt flow rate (230° C./2.16 kg) within the range from 20 g/10 min to 50g/10 min; 
 from 0.1 wt % to 5 wt %, by weight of the composition, of a propylene-based elastomer having within the range from 12 wt % to 20 wt % ethylene derived units and having a melting point temperature (T m ) of less than 110° C., wherein the propylene-based elastomer has a melt flow rate of greater than about 5 g/10 min; and 
 an ethylene-propylene copolymer comprising within the range from 45 wt % to 60 wt % ethylene derived units and having a Mooney Viscosity (1+4, 125° C.) of greater than about 20 Mooney units, and a weight average molecular weight (Mw) within a range of from 60,000 g/mole to 120,000 g/mole, 
 wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least four times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
 
     
     
       10. The thermoplastic polyolefin composition of  claim 9 , wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least ten times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
     
     
       11. The thermoplastic polyolefin composition of  claim 9 , wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least twenty times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
     
     
       12. The thermoplastic polyolefin composition of  claim 9 , wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least thirty times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
     
     
       13. The thermoplastic polyolefin composition of  claim 9 , wherein the room temperature notch impact of the composition is greater than about 9 ft-lb/in. 
     
     
       14. The thermoplastic polyolefin composition of  claim 9 , wherein the composition has a total ethylene content within the range of 6 wt % to 24 wt %. 
     
     
       15. The thermoplastic polyolefin composition of  claim 9 , wherein the a propylene-based elastomer has a melting point temperature (T m ) within the range of from 80° C. to 110° C. (first melt). 
     
     
       16. An automotive component made from the thermoplastic polyolefin composition of  claim 9 . 
     
     
       17. A method of injection molding an automotive component comprising melt extruding and injection molding the thermoplastic polyolefin composition of  claim 9 . 
     
     
       18. A thermoplastic polyolefin composition comprising:
 from 55 wt % to 75 wt %, by weight of the composition, of a polypropylene having a melting point temperature (T m ) of greater than 130° C. and a melt flow rate (230° C./2.16 kg) within the range from 20 g/10 min to 50 g/10 min; 
 from 0.1 wt % to 5 wt %, by weight of the composition, of a propylene-based elastomer having within the range from 12 wt % to 20 wt % ethylene derived units and having a melting point temperature (T m ) of less than 110° C., wherein the propylene-based elastomer has a melt flow rate of less than or equal to about 5 g/10 min; and 
 an ethylene-propylene copolymer comprising within the range from 45 wt % to 60 wt % ethylene derived units and having a Mooney Viscosity (1+4, 125° C.) of greater than about 20 Mooney units, and a weight average molecular weight (Mw) within a range of from 60,000 g/mole to 120,000 g/mole, 
 wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least four times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
 
     
     
       19. The thermoplastic polyolefin composition of  claim 18 , wherein the room temperature notch impact of the thermoplastic polyolefin composition is at least twenty times greater than the room temperature notch impact of a composition without the propylene-based elastomer. 
     
     
       20. The thermoplastic polyolefin composition of  claim 18 , wherein the composition has a total ethylene content within the range of 6 wt % to 24 wt %. 
     
     
       21. The thermoplastic polyolefin composition of  claim 18 , wherein the a propylene-based elastomer has a melting point temperature (Tm) within the range of from 80° C. to 110° C. (first melt).